pads off, copper grease the back, pads back on, squeaking gone.
^ that'll cure it for a bit but in my experience it'll come back.
I know the OP doesn't have them, but Brembo's are notorious for squealing (they do it from about 10 mph to stand still)
DONE! Mine stopped and never came back.
If they're cheap pads aswell they'll just keep on squeaking no matter what you do with copper grease.